Subcellular Microanatomy by 3D Deconvolution Brightfield Microscopy: Method and Analysis Using Human Chromatin in the Interphase Nucleus

Figure 5

The plasma cell clock-face or cart-wheel nuclear pattern as seen in 2D sections/projections from almost any angle can be explained by the multiradial arrangement of peripherally placed clump units. Top left shows 7 such units in a circle (some of these 7 will actually derive from peripheral clumps slightly out of the plane of the diagram). There is no central clump but these rings of clump units are arranged at multiple angles around the nucleus in 3D so that, at any angle of projection, there is likely to be a clump unit directly centred above or below (or both) the viewing plane and this creates the appearance of a central chromatin blob when seen in 2D projections (top right: the stippled clump is present at the periphery of the nucleus but in a plane that is perpendicular to the plane of the diagram). The bottom two panels show that even if much of the nucleus is cut away (as in a thin histology section) and we view it from the plane of that section (viewer “B” looking “down” onto the section) then we will still see a “clock-face” arrangement of clumps. Here, part of the conical extension of the bottom-most clump in the figure (labelled “A”) will form the central clump to the clock face even though it is only partially present due to the conical nature of these clump units and their radial orientation. From the viewpoint of observer “B” the stippled clump is now one of the peripheral “numerals” in the clock face and there will be a similar clump radially opposed to it out of the plane of the figure (not illustrated).